How do I add more than 8 channels to the VSE?
The VSE can have a lot more than 32 strips. You will find a scroll bar to the left of the VSE that you can use to scroll up/down through the list of strips.

Use  MMB to pan around the VSE.

Use &#9096; Ctrl MMB to scale the vse display, so that strips may be smaller/larger so that more strips can be visible at the same time.

This same control works the same in most editors.